As the third generation (3G) radio access scheme for cellular mobile communication, W-CDMA (Wideband Code Division Multiple Access) was standardized in 3GPP (3rd Generation Partnership Project), and cellular mobile communication service based on the scheme has been started. Further, in 3GPP, evolved 3G (Evolved Universal Terrestrial Radio Access; which will be referred to hereinbelow as “EUTRA”) and evolved 3G network (Evolved Universal Terrestrial Radio Access Network) have been investigated.
Applied to the EUTRA downlink in the direction of for communication from a base station apparatus to a mobile station apparatus, is an OFDM (Orthogonal Frequency Division Multiplexing) scheme for multi-carrier transmission. On the other hand, a DFT (Discrete Fourier Transmission)-Spread OFDM scheme for single carrier transmission is applied to the EUTRA uplink in the direction communication from a mobile station apparatus to the base station apparatus.
<UL TPC>
In EUTRA, transmission power control is applied to the uplink. In the transmissionpower control in the EUTRA uplink, the average transmission power of SC-FDMA symbols is controlled, and both the open loop transmission power control method and the closed loop transmission power control method are used.
The open loop transmission power control method is a method whereby the mobile station apparatus controls transmission power in accordance with the strength of the signal which the mobile station apparatus receives from the base station apparatus. In EUTRA, transmission power is controlled based on the pass loss calculated from the received power of the downlink reference signal received by the mobile station apparatus.
The closed loop transmission power control method is a method in which the base station apparatus sets up a transmission power control value in accordance with the strength of the signal received from a mobile station apparatus and transmits the transmission power control value to the mobile station apparatus using the downlink control channel while the mobile station apparatus controls transmission power in accordance with the transmission power control value included in the downlink control channel the mobile station receives. There are two control methods in EUTRA: one in which the mobile station apparatus controls transmission power using an accumulation of the transmission power control values that have been notified from the base station apparatus by a multiple number of downlink subframes; and the other in which the mobile station apparatus controls transmission power by directly using the transmission power control value that has been notified to the mobile station apparatus from the base station apparatus by a single downlink subframe. In EUTRA, the transmission power control value transmitted from the base station apparatus to the mobile station apparatus using the downlink control channel for representing radio resource allocation of the uplink shared data channel is formed of two bits. In the case where the mobile station apparatus uses the accumulation of the transmission power control values that have been notified from the base station apparatus by a multiple number of downlink subframes to control transmission power, the transmission power control value [dB] transmitted from the base station apparatus is represented by any value of {−1, 0, 1, 3}. In the case where the mobile station apparatus absolutely uses the transmission power control value that has been notified from the base station apparatus by a single downlink subframe, to control transmission power, the transmission power control value [dB] transmitted from the base station apparatus is represented by any value of {−4, −1, 1, 4}.
Further, in EUTRA, the mobile station apparatus controls the average transmission power of SC-FDMA symbols in accordance with the pass loss measured by the mobile station apparatus, and in addition to the parameter of the transmission power control value notified to the mobile station by the base station apparatus, the number of uplink resource block pairs allocated to the uplink shared data channel, the modulation scheme-dependent power offset value based on the modulation scheme applied to the uplink shared data channel, the reference transmission power control value notified to the mobile station apparatus by downlink shared data channel at the time of communication connection or the like, the coefficient to be multiplied with the pass loss measured by the mobile station apparatus, which is broadcast to the mobile station apparatuses within the communication area of the base station using the downlink shared data channel.
The mobile station apparatus compares the transmission power value calculated based on the above parameter with the permissible maximum transmission power value of the average transmission power of its own apparatus, and sets up a transmission power with the lower value.
<Component Carrier Aggregation>
Further, in 3GPP, investigation of the fourth generation (4th Generation; which will be referred to hereinbelow as “4G”) radio access scheme (Advanced EUTRA; which will be referred to hereinbelow as “A-EUTRA”) of cellular mobile communication and 4G network (Advanced EUTRAN) has begun.
In A-EUTRA, studies have been made aiming at supporting a wider frequency band range than that of EUTRA and securing compatibility with EUTRA. It has been also studied in A-EUTRA that the base station apparatus handles the EUTRA frequency band as one unit (which will be referred to hereinbelow as a component frequency band, and may be also called “Carrier Component” or “Component Carrier” and constructs a radio communication system from multiple component frequency bands (which may also be called as “Spectrum aggregation” or Carrier aggregation”). The base station apparatus performs communication with a mobile station apparatus that supports EUTRA, by way of any one of the component frequency bands, and also performs communication with a mobile station apparatus that supports A-EUTRA, by way of one or more of the component frequency bands.
In A-EUTRA, application of NxDFT-S-OFDM scheme to the uplink has been proposed (see Non-Patent Document 1, for example). The NxDFT-S-OFDM scheme is a scheme in which the mobile station apparatus transmits a signal using a multiple number of component frequency bands based on the DFT-S-OFDM scheme in each component frequency band and the base station apparatus receives the signal.